CONCOMITANT BORON-NEUTRON CAPTURE THERAPY DURING FAST-NEUTRON IRRADIATION OF A RAT GLIOMA

PURPOSE: Fast-neutron irradiation and boron-neutron capture therapy (B NCT) have been independently investigated as treatments for malignant disease. This study tested the feasibility of enhancing fast-neutron i rradiation with concomitant BNCT. MATERIALS AND METHODS: Seventeen mal e Fisher rats, each weighing 180-200 g and bearing 36B10 gliomas, were irradiated with graded doses of fast-neutron radiation. Half of the a nimals received an L-para-boronophenylalanine (BPA) fructose complex p rior to treatment. An in vitro colony-forming assay was used to measur e surviving fraction. RESULTS: A significantly lower surviving fractio n was noted in the tumors from the BPA group compared with those recei ving neutrons alone at the three lower neutron doses (P < .005). With use of a linear quadratic curve fit of cell survival, the dose modifyi ng factor was 1.32 at the 0.10 surviving fraction. Mean tumor boron co ncentration was 68.4 mu g/g. CONCLUSIONS: BNCT enhancement of fast-neu tron irradiation is feasible in an in vivo tumor system.